The light radiation theory of light emitting diode (LED) is to generate light from the energy released by the electron moving between an n-type semiconductor and a p-type semiconductor. Because the light radiation theory of LED is different from the incandescent light which heats the filament, the LED is called a “cold” light source. Moreover, the LED is more sustainable, longevous, light and handy, and less power-consumption, therefore it is considered as another option of the light source for the illumination markets. The LED applies to various applications like the traffic signal, backlight module, street light, and medical instruments, and is gradually replacing the traditional lighting sources.
FIG. 1 illustrates the structure of a conventional light emitting device 100 which includes a transparent substrate 10, a semiconductor stack 12 formed above the transparent substrate 10, and an electrode 14 formed above the semiconductor stack 12, wherein the semiconductor stack 12 comprises a first conductive-type semiconductor layer 120, an active layer 122, and a second conductive-type semiconductor layer 124.
In addition, the light emitting device 100 can be further connected to other components in order to form a light emitting apparatus.
The light-emitting device 100 may be mounted onto a submount by the side of the substrate 10, or a solder bump or a glue material may be formed between the submount and the light-emitting device 100, therefore a light-emitting apparatus is formed. Besides, the submount further comprises one circuit layout electrically connected to the electrode of the light-emitting device via an electrical conductive structure such as a metal wire.